Comment 3 for bug 896424

I have the same problem...

gnome-shell --replace
Advertencia del gestor de ventanas: Log level 8: shell_tray_manager_manage_stage: assertion `manager->priv->stage == NULL' failed
Advertencia del gestor de ventanas: Log level 16: Unable to register authentication agent: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: An authentication agent already exists for the given subject
Advertencia del gestor de ventanas: Log level 16: Error registering polkit authentication agent: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: An authentication agent already exists for the given subject (polkit-error-quark 0)
      JS LOG: GNOME Shell started at Tue Nov 29 2011 01:18:56 GMT-0200 (UYST)

(gnome-shell:5810): St-WARNING **: percentage lengths not currently supported

(gnome-shell:5810): St-WARNING **: percentage lengths not currently supported
gnome-shell-calendar-server[5819]: Got HUP on stdin - exiting
Violación de segmento

I have a 82865g Intel graphic.